Comparative law is not a body of rules but a method and a discipline: the systematic study of foreign legal systems — their structures, sources, concepts, institutions and functioning — in order to compare them, understand them, and learn from them. The comparativists' caution (the discipline's first lesson): comparison is not juxtaposition — listing French law and Nepali law side by side is not comparison until the tertium comparationis (the common measure — the function or problem both address) identifies what is being compared why. Law is compared functionally: not "what does the French Code call X" but "how does each system solve problem X."
Genesis (the discipline's own history):
1. Antiquity's comparisons: Aristotle's comparative study of Greek constitutions (158 polities collected for the Politics) — the method's ancestor;
2. The natural-law era: Grotius and Pufendorf comparing for the universal law of nations;
3. Montesquieu (1689–1755): the true father — De l'Esprit des Lois (1748): laws understood in their social, geographic and political context ("law must relate to the nature of the government... the climate... the religion... the commerce" of a people) — the sociological insight that law is a culture's product, not a free-standing text;
4. The nineteenth-century founding: the 1900 Paris Congress (Édouard Lambert and Raymond Saleilles's call for a droit commun de l'humanité — a common law of mankind through comparison); the national schools of comparative legislation (the Société de Législation Comparée, 1869);
5. The twentieth century's maturity: Zweigert and Kötz's Introduction to Comparative Law (the modern canon's "functional method"); René David's Grands systèmes (the families- classification tradition); Rudolf Schlesinger's common-core project; the Cold War's socialist-law studies; and the post-1989 and globalization eras' institutional explosion (the IACL, the world's comparative-law faculties, the UNIDROIT and Hague instruments' comparative foundations);
6. Nepal's comparative tradition: comparative law as Nepal's own legal history — the Muluki Ain's codification (1853) studying foreign models; the codes' successive importations (the Indian-statute family, the common-law procedure era, the 2074 Codes' global synthesis) — Nepal as a receiving jurisdiction, comparative law its constitutional habit (the Court citing foreign precedents).